Golf club head with face insert

CROSS REFERENCE TO RELATED APPLICATION

0001This application is a divisional of U.S. patent application Ser. No. 13/472,811, filed May 16, 2012, which is incorporated herein by reference.

FIELD

0002The disclosure pertains to golf clubs and methods of manufacturing golf clubs. More particularly, the disclosure pertains to face inserts for golf club heads, and methods of manufacturing face inserts for golf club heads.

BACKGROUND

0003Technologies have been developed for manufacturing face inserts for golf club heads. Conventional ways of making golf club heads that include face inserts include providing a club head body having a void or recess into which a face insert is placed, then attaching the face insert to the club head body via adhesive bonding, welding, or another attachment method. The face insert is typically formed by casting, forging, stamping, rolling, etc.

0004Traditionally, the striking zone of any iron or wedge face includes scoreline grooves, and some type of texturing on the face in between the scorelines to roughen the surface. The purpose of scoreline groove and texture on the striking zone is for the enhancement of ball spin, launch conditions, or performance by increasing the coefficient of friction between the ball cover and face. Conventional ways of making scoreline grooves include casting, forging, CNC milling, engraving, saw cutting, pressing, stamping, etc. Any texture on the face or in between grooves is usually created with a separate operation from the scoreline grooves to increase its surface roughness. Roughening the face surface is conventionally done by blasting (with various media, such as aluminum oxide, glass bead, zirconium bead, steel shot, or the like) or through a milling or fly-cutting machining operation. Microtexturing the face (process of making very fine texture patterns) can be achieved by milling or cutting, scratching, laser etching or chemical etching, or EDM.

0005Because of the two separate operations, the alignment between scorelines and microtexture features without interference with each other can be a challenge. Also, in order to optimize the performance of a golf club within the 2010 USGA rules, manufacturers seek operations with very tight manufacturing tolerance of scoreline dimensions and surface roughness to be as close as possible to the USGA limit. The tolerance of today's scoreline and roughness dimensions and repeatability of conventional methods often do not facilitate the highest performance requirement. Cutters or spinning tools used in scoreline engraving or fly cutting have limited life (3-7 heads only). Tool wear (even minor wear) can cause scoreline dimensions to be out of spec. Very often, scoreline grooves or microtexture formed do not conform to design specs or the USGA's rules. Creating face texture with milling operations can also lead to circular patterns which aren't consistent across the face, leading to variability in surface roughness at different locations.

0006The durability of scoreline grooves and microtexture is another challenge. Wearing out of microtexture or damage of scoreline grooves edges after sand bunker shots or thick turf shots is common. These can degrade performance. Although post face hardening processes or coatings, such as QPQ, or nitriding, or surface quenching, or plating, or PVD, can protect or improve durability, it is a challenge to maintain original dimensions and uniform hardness.

SUMMARY OF THE DESCRIPTION

0007Golf club heads comprise a club head body and a striking plate secured to the club head body. The striking plate comprises a contact plate defining at least a portion of a striking surface having a plurality of striking surface grooves. The striking plate is formed using an electroforming process.

0008According to a first aspect, a golf club head includes a club head body having a forward surface and a rear surface. A striking plate is secured to the forward surface of the club head body, the striking plate defining at least a portion of a striking surface having a plurality of striking surface grooves. The striking plate is formed of a metallic material that is suitable for use in an electroforming process. In some embodiments, the striking plate comprises an alloy of nickel and cobalt having a nickel concentration of at least about 55%, such as at least about 65%, such as at least about 75%, and a cobalt concentration of at least about 10%, such as at least about 20%, such as at least about 25%.

0009In one example of the first aspect, the striking plate comprises an alloy of nickel and cobalt having a nickel concentration that is between about 55% to about 90%, such as between about 65% to about 80%, such as from about 65% to about 75%, and a cobalt concentration that is between about 10% to about 45%, such as between about 20% to about 35%, such as between about 25% to about 35%.

0010In another example of the first aspect, the club head body includes a recessed region on the forward surface of the club head body, and the striking plate is secured to the club head body such that the striking plate resides within the recessed region.

0011According to a second aspect, a golf club head includes a club head body having a forward surface and a rear surface. One or more backing plates are provided, with the backing plate(s) having a forward surface and a rear surface. The rear surface of a backing plate is secured to the forward surface of the club head body. A striking plate is secured to the forward surface of the backing plate, the striking plate defining at least a portion of a striking surface having a plurality of striking surface grooves. The striking plate is formed of a metallic material that is suitable for use in an electroforming process. In some embodiments, the striking plate comprises an alloy of nickel and cobalt having a nickel concentration of at least about 55%, such as at least about 65%, such as at least about 75%, and a cobalt concentration of at least about 10%, such as at least about 20%, such as at least about 25%.

0012In one example of the second aspect, the striking plate comprises an alloy of nickel and cobalt having a nickel concentration that is between about 55% to about 90%, such as between about 65% to about 80%, such as from about 65% to about 75%, and a cobalt concentration that is between about 10% to about 45%, such as between about 20% to about 35%, such as between about 25% to about 35%.

0013In another example of the second aspect, the club head body includes a recessed region on the forward surface of the club head body, and the striking plate is secured to the club head body such that the striking plate resides within the recessed region.

0014In still other examples of the second aspect, the backing plate can be substantially flat on both its forward and rear surfaces, it can have a plurality of projections and recesses on its forward surface, it can have a plurality of through-holes having a variety of shapes and/or sizes, or it can have a combination of these features. The backing plate can be a metal, a metal alloy, a metallic material, an elastomer, a polymer, a rubber, a ceramic, a silicone, a fiber-glass, a multi-material combination, or mixtures or combinations of the foregoing materials.

0015In a third aspect of the present invention, a method of manufacturing a golf club head includes the steps of: providing a mandrel having a negative physical representation of a golf club striking plate; electroforming a striking plate using the mandrel; and attaching the electroformed striking plate to a body of the golf club head.

0016In an example of the third aspect, the step of providing a mandrel includes: providing a master of a golf club head striking plate; and manufacturing the mandrel from the master.

0017In another example of the third aspect, the step of manufacturing the mandrel includes electroforming the mandrel.

0018In still another example of the third aspect, the step of electroforming a striking plate includes: placing the mandrel into an electrolytic bath; electroforming a striking plate sheet using the mandrel, with the striking plate sheet comprising a plurality of striking plates; removing the striking plate sheet and mandrel from the electrolytic bath; and separating each of the plurality of striking plates from the striking plate sheet.

0019These and other features and aspects of the disclosed technology are set forth below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idref="DRAWINGS">FIG. 1A</figref> is an exploded view of a representative embodiment of an iron-type golf club head.

<figref idref="DRAWINGS">FIG. 1B</figref> is an elevational view of a head body of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 1A</figref>.

<figref idref="DRAWINGS">FIG. 1C</figref> is an elevational view of a striking plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 1A</figref>.

<figref idref="DRAWINGS">FIG. 1D</figref> is a sectional view of a portion of the striking plate of <figref idref="DRAWINGS">FIG. 1C</figref>.

<figref idref="DRAWINGS">FIG. 1E</figref> is an elevational view of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 1A</figref>.

<figref idref="DRAWINGS">FIG. 1F</figref> is a partial sectional view of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 1A</figref>.

<figref idref="DRAWINGS">FIG. 2A</figref> is an exploded view of another representative embodiment of an iron-type golf club head.

<figref idref="DRAWINGS">FIG. 2B</figref> is a sectional view of a portion of a striking plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 2A</figref>.

<figref idref="DRAWINGS">FIG. 2C</figref> is a sectional view of a portion of an intermediate plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 2A</figref>.

<figref idref="DRAWINGS">FIG. 2D</figref> is a partial sectional view of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 2A</figref>.

<figref idref="DRAWINGS">FIG. 3A</figref> is an exploded view of another representative embodiment of an iron-type golf club head.

<figref idref="DRAWINGS">FIG. 3B</figref> is a sectional view of a portion of a striking plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 3A</figref>.

<figref idref="DRAWINGS">FIG. 3C</figref> is a sectional view of a portion of an intermediate plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 3A</figref>.

<figref idref="DRAWINGS">FIG. 3D</figref> is a partial sectional view of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 3A</figref>.

<figref idref="DRAWINGS">FIG. 4A</figref> is an exploded view of another representative embodiment of an iron-type golf club head.

<figref idref="DRAWINGS">FIG. 4B</figref> is a sectional view of a portion of a striking plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 4A</figref>.

<figref idref="DRAWINGS">FIG. 4C</figref> is a sectional view of a portion of an intermediate plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 4A</figref>.

<figref idref="DRAWINGS">FIG. 4D</figref> is a partial sectional view of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 4A</figref>.

<figref idref="DRAWINGS">FIG. 5A</figref> is an exploded view of another representative embodiment of an iron-type golf club head.

<figref idref="DRAWINGS">FIG. 5B</figref> is a sectional view of a portion of a striking plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 5A</figref>.

<figref idref="DRAWINGS">FIG. 5C</figref> is a sectional view of a portion of an intermediate plate of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 5A</figref>.

<figref idref="DRAWINGS">FIG. 5D</figref> is a partial sectional view of the iron-type golf club head of <figref idref="DRAWINGS">FIG. 5A</figref>.

<figref idref="DRAWINGS">FIG. 6</figref> is a flowchart showing steps included in an embodiment of a method for manufacturing a golf club head.

DETAILED DESCRIPTION

0043Various embodiments and aspects of golf clubs and golf club heads of the inventions will be described with reference to details discussed below, and the accompanying drawings will illustrate the various embodiments. The following description and drawings are illustrative of the invention and are not to be construed as limiting the invention. Numerous specific details are described to provide a thorough understanding of various embodiments of the present invention. However, in certain instances, well-known or conventional details are not described in order to provide a concise discussion of embodiments of the present inventions.

0044Embodiments of an iron-type golf club head providing desired precision, durability, and manufacturability are described herein. In some embodiments, the iron-type golf club head has a striking plate or contact plate that is manufactured using an electroforming process, then attached to a club head body in a separate assembly step. The electroforming process provides the ability to manufacture striking plates (and other golf club components) with a high degree of precision, and to achieve manufacturing yield rates that are much higher than the rates achieved by previous striking plate manufacturing processes. In addition, in some embodiments, iron-type golf club head striking plates manufactured using an electroforming process achieve greater hardness and durability than comparable striking plates manufactured using previous processes.

0045Referring to <figref idref="DRAWINGS">FIGS. 1A-1F</figref>, a representative iron-type club head <b>100</b> includes a head body <b>110</b> and a striking plate or contact plate <b>130</b>. The head body <b>110</b> includes a heel <b>112</b>, a toe <b>113</b>, a top line <b>114</b>, a sole <b>116</b>, and a hosel <b>140</b> configured to attach the club head <b>100</b> to a shaft (not shown in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>). The head body <b>110</b> defines a striking plate mounting region <b>121</b> configured to receive the striking plate <b>130</b>. Club head mass may be distributed about the perimeter of the club body <b>110</b> based on a particular mass distribution for the club head <b>100</b> selected by a club head designer. Perimeter weighting can take various forms. One design includes a sole bar or other mass at or near the club head sole <b>116</b> to provide a center of gravity that is situated low in the club head <b>100</b> and behind the striking plate <b>130</b> as viewed from a striking surface <b>132</b> of the club head. Other designs include mass distributed to the heel <b>112</b> and/or toe <b>113</b> regions of the perimeter of the club head body <b>110</b> to achieve desired performance.

0046For convenience herein, positions and spacings of club components and features are described with respect to a club as situated in a normal address position with the sole <b>116</b> resting upon a flat ground plane. Directions from a club face toward a golf ball are referred to as forward, and directions away from the golf ball are referred to as rearward. Directions noted as up and down are vertically up and down with the club situated in the normal address position. As used herein, “normal address position” means the club head position wherein a vector normal to the center of the club face substantially lies in a first vertical plane (i.e., a vertical plane is perpendicular to the ground plane), a centerline axis of the hosel <b>140</b> substantially lies in a second vertical plane, and the first vertical plane and the second vertical plane substantially perpendicularly intersect. The center of the club face is determined using the procedures described in the USGA “Procedure for Measuring the Flexibility of a Golf Clubhead,” Revision 2.0, Mar. 25, 2005.

0047As shown in <figref idref="DRAWINGS">FIG. 1A</figref>, the striking plate <b>130</b> and the head body <b>110</b> are preferably formed separately. In such a design, the completed club head is made by securing the striking plate <b>130</b> to the mounting area <b>121</b> by bonding with an adhesive, welding, or other process. The mounting area <b>121</b> defines a recess, or pocket, formed in the forward surface of the club head body <b>110</b>. In the embodiment shown, the perimeter of the recess defined by the mounting area <b>121</b> is slightly larger than the perimeter of the striking plate <b>130</b>, thereby providing for the ability to position the striking plate <b>130</b> into the recess. A gap or seam <b>124</b> is thereby defined between the walls of the recess of the mounting area <b>121</b> and the perimeter of the striking plate <b>130</b>. In some embodiments, the seam <b>124</b> has a width that is preferably less than about 0.5 mm, such as less than about 0.25 mm, such as less than about 0.1 mm. In alternative embodiments, the club head body <b>110</b> does not include a recessed mounting area <b>121</b>. Instead, the striking plate <b>130</b> is secured directly to the forward-facing surface of the club head body <b>110</b>, and no gap or seam <b>124</b> is formed.

0048A front surface <b>122</b> of the club is defined by both a striking surface <b>132</b> of the striking plate <b>130</b> and portions <b>126</b>, <b>127</b> of the club body <b>110</b>. The front surface <b>122</b> can be polished, blasted using an abrasive media, or ground to remove any front surface edges situated at the striking plate/club body seam <b>124</b>. In some examples, the portions <b>126</b>, <b>127</b> are polished and the front surface <b>132</b> of the striking plate <b>130</b> is finely ground. In other examples, either or both of the portions <b>126</b>, <b>127</b> and the front surface <b>132</b> of the striking plate <b>130</b> and other portions of the club head may include a coating, such as a physical vapor deposition (PVD) coating using the processes described in U.S. patent application Ser. No. 11/749,723, filed on May 16, 2007, which is hereby incorporated by reference in its entirety. The striking surface <b>132</b> is a substantially planar grooved surface configured to strike a golf ball, although for some players, other portions of the front surface <b>122</b> also contact the golf ball.

0049As noted above, grinding, blasting, and/or polishing operations can be used to remove any excess material or irregularities introduced in the bonding, welding, or other process, or to provide a selected club head appearance such as, for example, a specularly reflective polished appearance, a fine ground appearance, or other appearance. Another alternative surface treatment includes applying a PVD coating to the striking plate <b>130</b> prior to attachment to the club head body <b>110</b>. For example, in some embodiments, a single layer of a titanium carbide containing material is applied having a thickness of less than 1 micrometer, such as about 0.4 to 0.6 micrometer. The striking plate <b>130</b> preferably includes a set of grooves, such as exemplary grooves <b>135</b>, <b>136</b> formed in the striking surface <b>132</b>. The striking plate <b>130</b> may also include an additional surface texture, such as secondary surface markings <b>137</b> (see, e.g., <figref idref="DRAWINGS">FIGS. 1D and 1F</figref>).

0050The thickness of the striking plate <b>130</b> can be selected to reduce mass associated with the striking plate <b>130</b>, so that additional mass can be distributed to other parts of the club head to achieve intended club design goals. The striking plate thickness is selected consistent with long term club use to avoid premature striking plate failure due to fatigue cracking and other such failure modes, and redistributed mass is situated low on the club head and rearward of the striking plate <b>130</b> or wherever needed to dictate a desired performance. In use, the striking plate <b>130</b> is subject to numerous high speed impacts with a golf ball, and should resist permanent deformation. Different types of irons (e.g., long irons and short irons) can experience different forces in golf ball impacts, and the striking plate thickness can be adjusted accordingly, if desired.

0051As described above, the striking plate <b>130</b> and the head body <b>110</b> are preferably formed separately. In some embodiments, the head body <b>110</b> is formed by casting, forging, stamping, or other known manufacturing process. Some examples of materials that can be used to form the head body <b>110</b> include, without limitation, carbon steels (e.g., 1020 or 8620 carbon steel), stainless steels (e.g., 304, 410, or 431 stainless steel), PH (precipitation-hardenable) alloys (e.g., 17-4, C450, or C455 alloys), titanium alloys (e.g., 3-2.5, 6-4, SP700, 15-3-3-3, 10-2-3, or other alpha/near alpha, alpha-beta, and beta/near beta titanium alloys), aluminum/aluminum alloys (e.g., 3000 series alloys, 5000 series alloys, 6000 series alloys, such as 6061-T6, and 7000 series alloys, such as 7075), magnesium alloys, copper alloys, nickel alloys, glass fiber reinforced polymers (GFRP), carbon fiber reinforced polymers (CFRP), metal matrix composites (MMC), ceramic matrix composites (CMC), and natural composites (e.g., wood composites). High strength materials having a relatively high modulus of elasticity (greater than about 50 GPa, 100 GPa, 150 GPa, 200 GPa, or 250 GPa) are generally preferred.

0052In the embodiment shown, the striking plate <b>130</b> is formed using an electroforming process. Electroforming is a metal forming process that forms objects by plating a metal layer onto a base form, known as a mandrel, which is removed after plating. Technically, it is a process of synthesizing a metal object by controlling the electrodeposition of metal passing through an electrolytic solution onto a metal or metalized form. The electroforming process differs from electroplating in that the object formed on the mandrel is much thicker and can exist as a self-supporting structure when the mandrel is removed. Electroforming provides the ability to replicate a mandrel surface precisely atom-by-atom with practically no loss of fidelity.

0053In the electroforming process, an electrolytic bath is used to deposit nickel, cobalt, nickel-cobalt alloy, or other electroplatable metal/metal alloy onto a conductive patterned surface, such as coated glass, stainless steel, or other conductive metallic surface. Once the plated material has been built up to the desired thickness, the electroformed part is stripped off the master substrate. This process allows high-quality duplication of the master and therefore permits quality production at low unit costs with high repeatability and excellent process control.

0054Electroforming achieves higher precision in comparison to other basic metal forming processes (e.g., casting, forging, stamping, and machining). For example, an electroformed member may be formed to dimensional tolerances, complexity, and/or light weight that are not possible with the foregoing metal forming processes. Electroformed metal and metal alloys also demonstrate superior properties over wrought metal due to their refined crystal structure. Multiple layers of electroformed metal can be molecularly bonded together, or to different substrate materials to produce complex structures with “grown-on” projections. Tolerances of 1.5 to 3 nanometers are possible.

0055As shown in <figref idref="DRAWINGS">FIG. 6</figref>, in a preferred method of electroforming a striking plate, a master is provided <b>610</b> using any known method, such as by forming scorelines or grooves and other surface texture markings onto a metal sheet (e.g., 304 stainless steel) by milling, etching, or other suitable methods. The surface markings on the master are constructed to a very tight tolerance, because they will be replicated very precisely during the electroforming process. In a preferred method, the master comprises a sheet having a length and width sufficient to accommodate several striking plates (e.g., about 4 to about 16 or more) being formed and subsequently cut into discrete striking plates from an electroformed sheet.

0056Once the master is manufactured, it may be used to construct one or more mandrels <b>620</b>. Each mandrel is constructed of a metal or metal alloy using an electroforming process. For example, the master may be placed into an electrolytic bath, and a metallic or metal alloy mandrel is grown on the surface of the master. In a preferred method, the mandrel is formed of a nickel-cobalt alloy discussed in more detail below, though other suitable electroforming materials may be used. Once the electroformed layer has grown to a thickness suitable for its use as a mandrel (e.g., from about 0.02 mm to about 6.35 mm thick, such as from about 0.20 mm to about 0.50 mm thick, such as about 0.25 mm thick), the master/mandrel is removed from the electrolytic bath, and the mandrel is removed from the master. The front (mating) surface of the mandrel is a precise negative of the front (mating) surface of the master, thereby allowing the mandrel to be used to create a striking plate sheet that has surface markings that are an exact replica of the master. The mandrel is then prepared for use in forming the striking plates. Additional mandrels may be manufactured using the master and the procedure described.

0057In the preferred method, one or more mandrels are then placed into an electrolytic bath, and a metallic or metal alloy striking plate sheet is grown on the surface of the mandrel <b>630</b>. As noted above, the striking plate sheet includes the identical surface markings that are contained on the master from which the mandrel was created, to a very high degree of precision. The striking plate sheet is formed to a desired thickness—i.e., the desired thickness of the striking plate discussed below—after which the electroformed striking plate sheet and mandrel are removed from the electrolytic bath. The striking plate sheet is then removed or separated from the mandrel <b>640</b>. The striking plate sheet is then prepared for cutting out individual striking plates, and the mandrel is prepared for re-use in electroforming additional striking plate sheets.

0058As noted above, in the preferred method, an electroformed striking plate sheet has a size and dimensions sufficient to accommodate a plurality of individual striking plates. For example, a single electroformed striking plate sheet may accommodate from about 4 to about 16 or more striking plates. After the electroformed striking plate sheet is removed from the mandrel, the individual striking plates are cut from the sheet <b>650</b>. In the preferred method, the striking plates are cut from the striking plate sheet via laser cutting, though other methods (e.g., die cutting, wire EDM, water jet, CNC milling, or the like) are used in alternative embodiments. The striking plates are then prepared for attachment to the club head body, such as by using a blasting media to enhance adhesion followed by a general cleaning, and are then attached via adhesive bonding, welding, or other suitable method <b>660</b>.

0059<figref idref="DRAWINGS">FIGS. 1C and 1D</figref> show an embodiment of a striking plate <b>130</b> produced using the electroforming processes described above. As shown, the striking plate <b>130</b> includes a plurality of scorelines or grooves <b>135</b>, <b>136</b> and an additional plurality of surface texture markings <b>137</b> formed on the forward striking surface <b>132</b>. Additionally, as a result of the electroforming process, the striking plate rear surface <b>133</b> includes a plurality of projections <b>138</b> defining a plurality of recesses <b>139</b> therebetween. Advantageously, all of the foregoing surface features located on the striking surface <b>132</b> and rear surface <b>133</b> of the striking plate <b>130</b> are formed simultaneously during the electroforming process. In conventional striking plate machining processes, the scorelines or grooves and any additional surface texture markings are cut or etched into the surfaces of the striking plate in separate processes after the striking plate is formed. By contrast, the electroforming processes described herein provide the ability to form the scorelines or grooves <b>135</b>, <b>136</b>, surface texture markings <b>137</b>, projections <b>138</b>, recesses <b>139</b>, and other striking plate surface features as a part of the same metal/metal alloy growing process by which the striking plate <b>130</b> is created during the electroforming process.

0060As noted above, the electroforming process includes creating a striking plate sheet grown on a mandrel in an electrolytic bath. There are a number of metals or metal alloys that are suitable for use in forming the electroformed striking plate sheet. Examples of suitable metals include nickel, cobalt, manganese, iron, and tungsten. Nickel alloys, for example, have higher strength by the addition of cobalt and/or manganese. In one embodiment, a suitable material is a cobalt-tungsten alloy. In some embodiments, the hardness of the striking plate ranges from about 300 HV (Vickers Hardness) to about 700 HV, or from about 30 HRC (Rockwell Scale) to about 60 HRC. In some embodiments, the striking plate sheet is formed of an alloy of nickel and cobalt having a nickel concentration of from about 90% to about 55%, and a cobalt concentration of from about 10% to about 45%. In some preferred embodiments, the nickel concentration is from about 80% to about 65%, such as from about 75% to about 65%, and the cobalt concentration is from about 20% to about 35%, such as from about 25% to about 35%. Some impurities may be present, but these are typically on the order of less than 1%. The striking plates <b>130</b> formed using these materials at these concentrations have a desirable hardness of about 500 HV (Vickers Hardness) or more.

0061In the embodiment shown in <figref idref="DRAWINGS">FIGS. 1C and 1D</figref>, the striking plate <b>130</b> is substantially flat, having a nominal front surface to rear surface thickness, t<b>1</b>, and a front surface to rear projection thickness, t<b>2</b>. The front surface to rear surface thickness t<b>1</b> is the cross-sectional thickness of the striking plate <b>130</b> as measured between a location on the front surface <b>132</b> between the land areas located between the scorelines or grooves <b>135</b>, <b>136</b> and other surface texture markings <b>137</b>, and a corresponding location defined at the bottom of a recess <b>139</b> on the rear surface <b>133</b> of the striking plate. The front surface to rear projection thickness t<b>2</b> is the cross-sectional thickness of the striking plate <b>130</b> as measured between a location on the front surface <b>132</b> between the land areas located between the scorelines or grooves <b>135</b>, <b>136</b> and other surface texture markings <b>137</b>, and a corresponding location defined at the outer surface of a projection <b>138</b> on the rear surface <b>133</b> of the striking plate.

0062The values for the front surface to rear surface thickness t<b>1</b> and front surface to rear projection thickness t<b>2</b> of the striking plate <b>130</b> will depend upon the electroforming process. The striking plate thickness is selected consistent with long term club use to avoid premature striking plate failure due to fatigue cracking and other such failure modes. In use, the striking plate <b>130</b> is subject to numerous high speed impacts with a golf ball, and should resist permanent deformation. In addition, different types of iron-type golf clubs (e.g., long irons, short irons, wedges) can experience different forces in golf ball impacts, and the striking plate thickness can be adjusted accordingly, as desired. In several preferred embodiments, the value for the front surface to rear surface thickness, t<b>1</b>, is from about 0.20 to about 0.50 mm, such as from about 0.20 to about 0.40 mm, such as from about 0.20 to about 0.30 mm. In several preferred embodiments, the value for the front surface to rear projection thickness, t<b>2</b>, is from about 0.25 to about 1.00 mm, such as from about 0.40 to about 0.90 mm, such as from about 0.50 to about 0.80 mm.

0063The electroforming processes described herein are capable of providing scorelines or grooves <b>135</b>, <b>136</b> and/or surface texture markings <b>137</b> and other features having a broad range of sizes and shapes, and/or having a broad range of cross-sectional profiles. Advantageously, the electroforming processes described herein are capable of providing these designs with a high degree of precision, and with a manufacturing yield that is much higher than the manufacturing yield provided by conventional striking plate manufacturing methods, such as casting, forging, milling, etc.

0064In the embodiments shown, the scorelines or grooves <b>135</b>, <b>136</b> and surface texture markings <b>137</b> each have bottom surfaces and side walls that define nominal depth and width dimensions. The transitions between the bottom surfaces and the side walls are radiused to provide smooth transitions. The scorelines or grooves <b>135</b>, <b>136</b>, for example, may include radii of curvature that are typically less than about 0.55 mm, such as less than about 0.50 mm. In several embodiments, the scorelines or grooves <b>135</b>, <b>136</b> have a depth of from about 0.01 mm to about 0.50 mm, and a width of less than about 0.90 mm, such as from about 0.50 mm to about 0.90 mm. Additional embodiments and details concerning the size and shape of the scorelines or grooves is set forth in U.S. Pat. No. 6,814,673, which is incorporated by reference herein.

0065The surface texture markings <b>137</b> also have bottom surfaces and side walls that define nominal depth and width dimensions. In several embodiments, the surface texture markings <b>137</b> have a geometric shape having a depth of from about 0.005 mm to about 0.018 mm, and a width of from about 0.10 mm to about 0.20 mm. The geometric shapes preferably all have the same size and shape, preferably square or diamond, although other shapes, e.g., circles, triangles, etc. and/or varieties of shapes and/or sizes, alternatively could be used. The geometric shapes are preferably uniformly distributed over the reference areas of the front surface <b>132</b> of the striking plate, which is defined between each pair of adjacent scorelines or grooves <b>135</b>, <b>136</b>. In other alternative embodiments, the front surface <b>132</b> of the striking plate includes an engineered texture such as the geometric shapes, designs, and patterns described in U.S. Pat. No. 7,445,561, which is incorporated by reference herein. In practical examples, the grooves <b>135</b>, <b>136</b> and surface texture markings <b>137</b> have dimensions, transition radii, and other parameters selected so as to conform to the Rules of Golf.

0066In the embodiments shown in <figref idref="DRAWINGS">FIGS. 1D and 1F</figref>, the rear surface <b>133</b> of the striking plate includes a plurality of projections <b>138</b> defining a plurality of recesses <b>139</b> therebetween. The projections <b>138</b> on the rear surface <b>133</b> are generally aligned with the scorelines or grooves <b>135</b>, <b>136</b> on the front surface <b>132</b> of the striking plate. In the embodiments shown, the projections <b>138</b> are generally wider than the corresponding scorelines or grooves <b>135</b>, <b>136</b>, having a width t<b>3</b> of from about 0.70 mm to about 1.50 mm. The recesses <b>139</b>, on the other hand, will have a width, t<b>4</b>, that is generally narrower than the spacing between adjacent scorelines or grooves <b>135</b>, <b>136</b> on the front surface of the striking plate. The cross-sections of the rear surface projections <b>138</b> and recesses <b>139</b> shown in <figref idref="DRAWINGS">FIG. 1D</figref> are merely one example, as square, trapezoidal, semicircular, triangular, or other shapes for the projections and/or recesses can be used. Moreover, different cross-sectional shapes and dimensions can be used in different portions of the striking plate <b>130</b>.

0067<figref idref="DRAWINGS">FIG. 1F</figref> shows a partial cross-section of the striking plate <b>130</b> after it has been attached to the club head body <b>110</b>. The striking plate <b>130</b> may be attached to the club head body <b>110</b> by adhesive bonding, welding, brazing, soldering, diffusion bonding, mechanical fastening, riveting, screwing, etc. In the embodiment shown, the striking plate <b>130</b> is attached to the club head body <b>110</b> by a layer of adhesive material <b>134</b>, such as an epoxy or polyurethane adhesive. For example, in an embodiment, the adhesive material <b>134</b> is 3M® DP460, though other suitable adhesive materials may be used. The adhesive <b>134</b> is applied so as to fill the gap completely between the striking plate <b>130</b> and the club head body <b>110</b> within the mounting region <b>121</b>. The thickness of the layer of adhesive material <b>134</b> is preferably between about 0.05 mm to about 0.4 mm, such as from about 0.07 mm to about 0.15 mm, such as about 0.1 mm. In embodiments in which the adhesive layer <b>134</b> has a non-uniform thickness, such as the embodiment shown in <figref idref="DRAWINGS">FIG. 1F</figref>, the foregoing measurements would apply to the area of the thinnest layer of adhesive material. To enhance the bonding strength of the adhesive, in some embodiments, the rear surface <b>133</b> of the striking plate and/or the surface of the mounting region <b>121</b> of the club head body are treated prior to attachment of the striking plate. For example, in some embodiments, the rear surface <b>133</b> of the striking face is subjected to a media blasting process, e.g., using sand or ceramic glass beads to slightly roughen the surface to enhance the strength of the adhesive bond. In one embodiment, the rear surface <b>133</b> of the striking face is subjected to a media blast using low pressure and a grit size of between about 100 mesh to about 400 mesh, such as, for example, between about 180 mesh and about 320 mesh, prior to bonding the striking plate <b>130</b> to the club head body <b>110</b>.

0068In some embodiments, one or more optional backing plates are positioned between the striking plate and the head body. For example, in several embodiments, one, two, three, or four or more backing plates are positioned between the striking plate and the head body. The one or more optional backing plates may be included to obtain any of several performance advantages, such as to improve the durability of the striking plate and/or the club head, to improve the sound or feel of the club head upon impact with a golf ball, or to improve other performance objectives. These performance advantages can be achieved, or enhanced, by providing one or more backing plates having particular structures, geometries, materials, material properties, etc.

0069Some examples of materials that can be used to form the one or more optional backing plates described herein include, without limitation: metals (e.g., titanium, steel, aluminum, magnesium, etc.); metal alloys (e.g., nickel alloys, cobalt alloys, molybdenum alloys, combinations, etc.); metallic materials; viscoelastic elastomers; vinyl copolymers with or without inorganic fillers; polyvinyl acetate with or without mineral fillers such as barium sulfate; acrylics; polyesters; polyurethanes; polyethers; polyamides; polybutadienes; polystyrenes; polyisoprenes; polyethylenes; polyolefins; styrene/isoprene block copolymers; metallized polyesters; metallized acrylics; epoxies; epoxy and graphite composites; natural and synthetic rubbers; ceramic materials; piezoelectric ceramics; thermoset and thermoplastic polymers or rubbers; foamed polymers; ionomers; low-density fiber glass; bitumen; silicone; multi-material combinations; and mixtures or combinations thereof. The metallized polyesters and acrylics can comprise aluminum as the metal. Commercially available materials include resilient polymeric materials such as Scotchdamp™ from 3M, Sorbothane® from Sorbothane, Inc., DYAD® and GP® from Soundcoat Company Inc., Dynamat® from Dynamat Control of North America, Inc., NoViFlex™ Sylomer® from Pole Star Maritime Group, LLC, Isoplast® from The Dow Chemical Company, and Legetolex™ from Piqua Technologies, Inc.

0070Referring to <figref idref="DRAWINGS">FIGS. 2A-2D</figref>, another embodiment of a representative iron-type club head <b>200</b> includes a head body <b>210</b> and a striking plate or contact plate <b>230</b>. The head body <b>210</b> includes a heel <b>212</b>, a toe <b>213</b>, a top line <b>214</b>, a sole <b>216</b>, and a hosel <b>240</b> configured to attach the club head <b>200</b> to a shaft (not shown in <figref idref="DRAWINGS">FIGS. 2A-2D</figref>). The head body <b>210</b> defines a striking plate mounting region <b>221</b> configured to receive the striking plate <b>230</b> and an optional backing plate <b>250</b>. Club head mass may be distributed about the perimeter of the club body <b>210</b> based on a particular mass distribution for the club head <b>200</b> selected by a club head designer, as discussed previously in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.

0071As shown in <figref idref="DRAWINGS">FIG. 2A</figref>, the striking plate <b>230</b>, the optional backing plate <b>250</b>, and the head body <b>210</b> are preferably formed separately. In such a design, the completed club head is made by securing the striking plate <b>230</b> and the optional backing plate <b>250</b> to the mounting area <b>221</b> by bonding with an adhesive, welding, or other process. The mounting area <b>221</b> defines a recess, or pocket, formed in the forward surface of the club head body <b>210</b>. In the embodiment shown, the perimeter of the recess defined by the mounting area <b>221</b> is slightly larger than the perimeter of the striking plate <b>230</b> and the optional backing plate <b>250</b>, thereby providing for the ability to position the striking plate <b>230</b> and backing plate <b>250</b> into the recess. A gap or seam <b>224</b> is thereby defined between the walls of the recess of the mounting area <b>221</b> and the perimeter of the striking plate <b>230</b>. In some embodiments, the seam <b>224</b> has a width that is preferably less than about 0.5 mm, such as less than about 0.25 mm, such as less than about 0.1 mm. In alternative embodiments, the club head body <b>210</b> does not include a recessed mounting area <b>221</b>. Instead, the striking plate <b>230</b> and optional backing plate <b>250</b> are secured directly to the forward-facing surface of the club head body <b>210</b>, and no gap or seam <b>224</b> is formed.

0072A front surface <b>222</b> of the club is defined by both a striking surface <b>232</b> of the striking plate <b>230</b> and portions <b>226</b> of the club body <b>210</b>. The front surface <b>222</b> can be polished, blasted using an abrasive media, or ground to remove any front surface edges situated at the striking plate/club body seam <b>224</b>. In some examples, the portions <b>226</b> are polished and the front surface <b>232</b> of the striking plate <b>230</b> is finely ground. The striking surface <b>232</b> is a substantially planar grooved surface configured to strike a golf ball, although for some players, other portions of the front surface <b>222</b> also contact the golf ball.

0073As noted above, grinding, blasting, polishing, and/or coating (e.g., PVD coating) operations can be used to remove any excess material or irregularities introduced in the bonding, welding, or other process, or to provide a selected club head appearance such as, for example, a specularly reflective polished appearance, a fine ground appearance, a darkened or black appearance, or other appearance. The striking plate <b>230</b> preferably includes a set of grooves, such as exemplary grooves <b>235</b>, <b>236</b> formed in the striking surface <b>232</b>. The striking plate <b>230</b> may also include an additional surface texture, such as secondary surface markings <b>237</b> (see, e.g., <figref idref="DRAWINGS">FIGS. 2B and 2D</figref>). The grooves <b>235</b>, <b>236</b> and secondary surface markings <b>237</b> are similar to those described previously in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.

0074In some embodiments, the head body <b>210</b> is formed by casting, forging, stamping, or other known manufacturing process, using the processes and materials described above in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. Similarly, in the embodiment shown, the striking plate <b>230</b> is formed using an electroforming process, which is also described above in relation to the embodiments illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. The striking plate <b>230</b> includes pluralities of projections <b>238</b> and recesses <b>239</b> on its rear surface, and includes thickness ranges for the thicknesses t<b>1</b>, t<b>2</b>, t<b>3</b>, and t<b>4</b> as described above in relation to the striking plate <b>130</b> illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. The cross-sections of the rear surface projections <b>238</b> and recesses <b>239</b> shown in <figref idref="DRAWINGS">FIG. 2B</figref> are merely one example, as square, trapezoidal, semicircular, triangular, or other shapes for the projections and/or recesses can be used. Moreover, different cross-sectional shapes and dimensions can be used in different portions of the striking plate <b>230</b>.

0075Turning to <figref idref="DRAWINGS">FIGS. 2C-2D</figref>, the optional backing plate <b>250</b> includes a forward surface <b>252</b> and a rear surface <b>253</b>. In the embodiment shown, the backing plate <b>250</b> is substantially flat on both its forward surface <b>252</b> and rear surface <b>253</b>, having a substantially uniform thickness t<b>5</b>. The thickness t<b>5</b> will be dependent upon the material of the backing plate and the desired performance objective for including the backing plate, among other factors. In several embodiments, the backing plate <b>250</b> has a thickness of from about 0.1 mm to about 3.0 mm, such as from about 0.5 mm to about 2.0 mm, such as from about 1.0 mm to about 1.5 mm. The striking plate <b>230</b> and backing plate <b>250</b> can be attached to the club head body <b>210</b> by adhesive bonding, soldering, brazing, welding, mechanical fastening, riveting, screwing, etc. In the embodiment shown in <figref idref="DRAWINGS">FIG. 2D</figref>, the backing plate <b>250</b> is attached to the club head body <b>210</b> by a first adhesive layer <b>254</b>, and the striking plate <b>230</b> is attached to the backing plate <b>250</b> by a second adhesive layer <b>234</b>. The adhesive materials used in the first adhesive layer <b>254</b> and second adhesive layer <b>234</b> can be the same as those used in the adhesive layer <b>134</b> described above in relation to the embodiments illustrated in <figref idref="DRAWINGS">FIGS. 1A-F</figref>.

0076Referring to <figref idref="DRAWINGS">FIGS. 3A-3D</figref>, another embodiment of a representative iron-type club head <b>300</b> includes a head body <b>310</b> and a striking plate or contact plate <b>330</b>. The head body <b>310</b> includes a heel <b>312</b>, a toe <b>313</b>, a top line <b>314</b>, a sole <b>316</b>, and a hosel <b>340</b> configured to attach the club head <b>300</b> to a shaft (not shown in <figref idref="DRAWINGS">FIGS. 3A-3D</figref>). The head body <b>310</b> defines a striking plate mounting region <b>321</b> configured to receive the striking plate <b>330</b> and an optional backing plate <b>350</b>. Club head mass may be distributed about the perimeter of the club body <b>310</b> based on a particular mass distribution for the club head <b>300</b> selected by a club head designer, as discussed previously in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.]

0077As shown in <figref idref="DRAWINGS">FIG. 3A</figref>, the striking plate <b>330</b>, the optional backing plate <b>350</b>, and the head body <b>310</b> are preferably formed separately. In such a design, the completed club head is made by securing the striking plate <b>330</b> and the optional backing plate <b>350</b> to the mounting area <b>321</b> by bonding with an adhesive, welding, or other process. The mounting area <b>321</b> defines a recess, or pocket, formed in the forward surface of the club head body <b>310</b>. In the embodiment shown, the perimeter of the recess defined by the mounting area <b>321</b> is slightly larger than the perimeter of the striking plate <b>330</b> and the optional backing plate <b>350</b>, thereby providing for the ability to position the striking plate <b>330</b> and backing plate <b>350</b> into the recess. A gap or seam <b>324</b> is thereby defined between the walls of the recess of the mounting area <b>321</b> and the perimeter of the striking plate <b>330</b>. In some embodiments, the seam <b>324</b> has a width that is preferably less than about 0.5 mm, such as less than about 0.25 mm, such as less than about 0.1 mm. In alternative embodiments, the club head body <b>310</b> does not include a recessed mounting area <b>321</b>. Instead, the striking plate <b>330</b> and optional backing plate <b>350</b> are secured directly to the forward-facing surface of the club head body <b>310</b>, and no gap or seam <b>324</b> is formed.

0078A front surface <b>322</b> of the club is defined by both a striking surface <b>332</b> of the striking plate <b>330</b> and portions <b>326</b> of the club body <b>310</b>. The front surface <b>322</b> can be polished, blasted using an abrasive media, or ground to remove any front surface edges situated at the striking plate/club body seam <b>324</b>. In some examples, the portions <b>326</b> are polished and the front surface <b>332</b> of the striking plate <b>330</b> is finely ground. The striking surface <b>332</b> is a substantially planar grooved surface configured to strike a golf ball, although for some players, other portions of the front surface <b>322</b> also contact the golf ball.

0079As noted above, grinding, blasting, polishing, and/or coating (e.g., PVD coating) operations can be used to remove any excess material or irregularities introduced in the bonding, welding, or other process, or to provide a selected club head appearance such as, for example, a specularly reflective polished appearance, a fine ground appearance, a black or darkened appearance, or other appearance. The striking plate <b>330</b> preferably includes a set of grooves, such as exemplary grooves <b>335</b>, <b>336</b> formed in the striking surface <b>332</b>. The striking plate <b>330</b> may also include an additional surface texture, such as secondary surface markings <b>337</b> (see, e.g., <figref idref="DRAWINGS">FIGS. 3B and 3D</figref>). The grooves <b>335</b>, <b>336</b> and secondary surface markings <b>337</b> are similar to those described previously in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.

0080In some embodiments, the head body <b>310</b> is formed by casting, forging, stamping, or other known manufacturing process, using the processes and materials described above in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. Similarly, in the embodiment shown, the striking plate <b>330</b> is formed using an electroforming process, which is also described above in relation to the embodiments illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. The striking plate <b>330</b> includes pluralities of projections <b>338</b> and recesses <b>339</b> on its rear surface, and includes thickness ranges for the thicknesses t<b>1</b>, t<b>2</b>, t<b>3</b>, and t<b>4</b> as described above in relation to the striking plate <b>130</b> illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.

0081Turning to <figref idref="DRAWINGS">FIGS. 3C-3D</figref>, the optional backing plate <b>350</b> includes a forward surface <b>352</b> and a rear surface <b>353</b>. In the embodiment shown, the backing plate <b>350</b> is substantially flat on its rear surface <b>353</b>, and includes a plurality of projections <b>356</b> and recesses <b>357</b> on its forward surface <b>352</b>. In some embodiments, the thickness t<b>6</b> of the backing plate <b>350</b> at the location of a recess <b>357</b> may be from about 0.1 mm to about 3.0 mm, such as from about 0.20 mm to about 2.0 mm, such as from about 0.25 mm to about 1.0 mm. In some embodiments, the thickness t<b>7</b> of the backing plate <b>350</b> at a location of a projection <b>356</b> may be from about 0.25 mm to about 3.25 mm, such as from about 0.40 mm to about 2.5 mm, such as from about 0.50 mm to about 1.0 mm. In some embodiments, the width (t<b>8</b>) of the recesses <b>357</b> is substantially equal to the width of the reference areas between the grooves <b>335</b>, <b>336</b> formed on the striking surface of the striking plate <b>330</b>, and the width (t<b>9</b>) of the projections <b>356</b> is substantially equal to the width of the grooves <b>335</b>, <b>336</b> on the striking plate <b>330</b>. The locations, sizes, and cross-sectional shapes of the forward surface projections <b>356</b> and recesses <b>357</b> shown in <figref idref="DRAWINGS">FIGS. 3C-3D</figref> are merely one example, as square, trapezoidal, semicircular, triangular, or other shapes for the projections and/or recesses can be used. Moreover, different cross-sectional shapes and dimensions can be used in different portions of the backing plate <b>350</b>.

0082As shown, for example, in <figref idref="DRAWINGS">FIG. 3D</figref>, in some embodiments, the projections <b>356</b> and recesses <b>357</b> on the forward surface of the backing plate are generally aligned, center-to-center, with respective ones of the recesses <b>339</b> and projections <b>338</b> formed on the rear surface of the striking plate <b>330</b>, respectively. As a result, the adhesive layer <b>334</b> located between the striking plate <b>330</b> and the backing plate <b>350</b> may have a substantially uniform thickness across the contact area between the adhesive layer <b>334</b> and the backing plate <b>350</b> and striking plate <b>330</b>. In other embodiments, such as described below in reference to <figref idref="DRAWINGS">FIG. 4D</figref>, the alignment of the projections and recesses are reversed, such that the respective projections are aligned with each other and the respective recesses are aligned with each other. As discussed below, the alignment of the striking plate and backing plate, as well as the striking plate projections and recesses and backing plate projections and recesses, may be varied to provide one or more desired performance objectives.

0083The backing plate thicknesses t<b>6</b>, t<b>7</b> will be dependent upon the material of the backing plate <b>350</b> and the desired performance objectives for including the backing plate, among other factors. The striking plate <b>330</b> and backing plate <b>350</b> can be attached to the club head body <b>310</b> by adhesive bonding, soldering, brazing, welding, mechanical fastening, riveting, screwing, etc. In the embodiment shown in <figref idref="DRAWINGS">FIG. 3D</figref>, the backing plate <b>350</b> is attached to the club head body <b>310</b> by a first adhesive layer <b>354</b>, and the striking plate <b>330</b> is attached to the backing plate <b>350</b> by a second adhesive layer <b>334</b>. The adhesive materials used in the first adhesive layer <b>354</b> and second adhesive layer <b>334</b> can be the same as those used in the adhesive layer <b>134</b> described above in relation to the embodiments illustrated in <figref idref="DRAWINGS">FIGS. 1A-F</figref>.

0084Referring to <figref idref="DRAWINGS">FIGS. 4A-4D</figref>, another embodiment of a representative iron-type club head <b>400</b> includes a head body <b>410</b> and a striking plate or contact plate <b>430</b>. The head body <b>410</b> includes a heel <b>412</b>, a toe <b>413</b>, a top line <b>414</b>, a sole <b>416</b>, and a hosel <b>440</b> configured to attach the club head <b>400</b> to a shaft (not shown in <figref idref="DRAWINGS">FIGS. 4A-4D</figref>). The head body <b>410</b> defines a striking plate mounting region <b>421</b> configured to receive the striking plate <b>430</b> and an optional backing plate <b>450</b>. Club head mass may be distributed about the perimeter of the club body <b>410</b> based on a particular mass distribution for the club head <b>400</b> selected by a club head designer, as discussed previously in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.

0085As shown in <figref idref="DRAWINGS">FIG. 4A</figref>, the striking plate <b>430</b>, the optional backing plate <b>450</b>, and the head body <b>410</b> are preferably formed separately. In such a design, the completed club head is made by securing the striking plate <b>430</b> and the optional backing plate <b>450</b> to the mounting area <b>421</b> by bonding with an adhesive, welding, or other process. The mounting area <b>421</b> defines a recess, or pocket, formed in the forward surface of the club head body <b>410</b>. In the embodiment shown, the perimeter of the recess defined by the mounting area <b>421</b> is slightly larger than the perimeter of the striking plate <b>430</b> and the optional backing plate <b>450</b>, thereby providing for the ability to position the striking plate <b>430</b> and backing plate <b>450</b> into the recess. A gap or seam <b>424</b> is thereby defined between the walls of the recess of the mounting area <b>421</b> and the perimeter of the striking plate <b>430</b>. In some embodiments, the seam <b>424</b> has a width that is preferably less than about 0.5 mm, such as less than about 0.25 mm, such as less than about 0.1 mm. In alternative embodiments, the club head body <b>410</b> does not include a recessed mounting area <b>421</b>. Instead, the striking plate <b>430</b> and optional backing plate <b>450</b> are secured directly to the forward-facing surface of the club head body <b>410</b>, and no gap or seam <b>424</b> is formed.

0086A front surface <b>422</b> of the club is defined by both a striking surface <b>432</b> of the striking plate <b>430</b> and portions <b>426</b> of the club body <b>410</b>. The front surface <b>422</b> can be polished, blasted using an abrasive media, or ground to remove any front surface edges situated at the striking plate/club body seam <b>424</b>. In some examples, the portions <b>426</b> are polished and the front surface <b>432</b> of the striking plate <b>430</b> is finely ground. The striking surface <b>432</b> is a substantially planar grooved surface configured to strike a golf ball, although for some players, other portions of the front surface <b>422</b> also contact the golf ball.

0087As noted above, grinding, blasting, polishing, and/or coating (e.g., PVD coating) operations can be used to remove any excess material or irregularities introduced in the bonding, welding, or other process, or to provide a selected club head appearance such as, for example, a specularly reflective polished appearance, a fine ground appearance, a black or darkened appearance, or other appearance. The striking plate <b>430</b> preferably includes a set of grooves, such as exemplary grooves <b>435</b>, <b>436</b> formed in the striking surface <b>432</b>. The striking plate <b>430</b> may also include an additional surface texture, such as secondary surface markings <b>437</b> (see, e.g., <figref idref="DRAWINGS">FIGS. 4B and 4D</figref>). The grooves <b>435</b>, <b>436</b> and secondary surface markings <b>437</b> are similar to those described previously in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.

0088In some embodiments, the head body <b>410</b> is formed by casting, forging, stamping, or other known manufacturing process, using the processes and materials described above in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. Similarly, in the embodiment shown, the striking plate <b>430</b> is formed using an electroforming process, which is also described above in relation to the embodiments illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. The striking plate <b>430</b> includes pluralities of projections <b>438</b> and recesses <b>439</b> on its rear surface, and includes thickness ranges for the thicknesses t<b>1</b>, t<b>2</b>, t<b>3</b>, and t<b>4</b> as described above in relation to the striking plate <b>130</b> illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. The cross-sections of the rear surface projections <b>438</b> and recesses <b>439</b> shown in <figref idref="DRAWINGS">FIG. 4B</figref> are merely one example, as square, trapezoidal, semicircular, triangular, or other shapes for the projections and/or recesses can be used. Moreover, different cross-sectional shapes and dimensions can be used in different portions of the striking plate <b>430</b>.

0089Turning to <figref idref="DRAWINGS">FIGS. 4C-4D</figref>, the optional backing plate <b>450</b> includes a forward surface <b>452</b> and a rear surface <b>453</b>. In the embodiment shown, the backing plate <b>450</b> is substantially flat on its rear surface <b>453</b>, and includes a plurality of projections <b>456</b> and recesses <b>457</b> on its forward surface <b>452</b>. In some embodiments, the thickness t<b>10</b> of the backing plate <b>450</b> at the location of a recess <b>457</b> may be from about 0.1 mm to about 3.0 mm, such as from about 0.20 mm to about 2.0 mm, such as from about 0.25 mm to about 1.0 mm. In some embodiments, the thickness t<b>11</b> of the backing plate <b>450</b> at a location of a projection <b>456</b> may be from about 0.25 mm to about 3.25 mm, such as from about 0.40 mm to about 2.5 mm, such as from about 0.50 mm to about 1.0 mm. In some embodiments, the width (t<b>12</b>) of the recesses <b>457</b> is substantially equal to the width of the recesses <b>439</b> formed on the rear surface of the striking plate <b>430</b>, and the width (t<b>13</b>) of the projections <b>456</b> is substantially equal to the width of the projections <b>438</b> formed on the rear surface of the striking plate <b>430</b>. The locations, sizes, and cross-sectional shapes of the forward surface projections <b>456</b> and recesses <b>457</b> shown in <figref idref="DRAWINGS">FIGS. 4C-4D</figref> are merely one example, as square, trapezoidal, semicircular, triangular, or other shapes for the projections and/or recesses can be used. Moreover, different cross-sectional shapes and dimensions can be used in different portions of the backing plate <b>450</b>.

0090The backing plate thicknesses t<b>10</b>, t<b>11</b> will be dependent upon the material of the backing plate <b>450</b> and the desired performance objectives for including the backing plate, among other factors. The striking plate <b>430</b> and backing plate <b>450</b> can be attached to the club head body <b>410</b> by adhesive bonding, soldering, brazing, welding, mechanical fastening, riveting, screwing, etc. In the embodiment shown in <figref idref="DRAWINGS">FIG. 4D</figref>, the backing plate <b>450</b> is attached to the club head body <b>410</b> by a first adhesive layer <b>454</b>, and the striking plate <b>430</b> is attached to the backing plate <b>450</b> by a second adhesive layer <b>434</b>. The adhesive materials used in the first adhesive layer <b>454</b> and second adhesive layer <b>434</b> can be the same as those used in the adhesive layer <b>134</b> described above in relation to the embodiments illustrated in <figref idref="DRAWINGS">FIGS. 1A-F</figref>.

0091As shown, for example, in <figref idref="DRAWINGS">FIG. 4D</figref>, in some embodiments, the projections <b>456</b> and recesses <b>457</b> on the forward surface of the backing plate are generally aligned, center-to-center, with respective ones of the projections <b>438</b> and recesses <b>439</b> formed on the rear surface of the striking plate <b>430</b>, respectively. As a result, the adhesive layer <b>434</b> located between the striking plate <b>430</b> and the backing plate <b>450</b> may have a thickness that alternates between relatively thin sections of the adhesive layer <b>434</b> located between aligned striking plate rear projections <b>438</b> and backing plate forward projections <b>456</b>, and relatively thick sections of the adhesive layer <b>434</b> located between aligned striking plate rear recesses <b>439</b> and backing plate forward recesses <b>457</b>.

0092Referring to <figref idref="DRAWINGS">FIGS. 5A-5D</figref>, another embodiment of a representative iron-type club head <b>500</b> includes a head body <b>510</b> and a striking plate or contact plate <b>530</b>. The head body <b>510</b> includes a heel <b>512</b>, a toe <b>513</b>, a top line <b>514</b>, a sole <b>516</b>, and a hosel <b>540</b> configured to attach the club head <b>500</b> to a shaft (not shown in <figref idref="DRAWINGS">FIGS. 5A-5D</figref>). The head body <b>510</b> defines a striking plate mounting region <b>521</b> configured to receive the striking plate <b>530</b> and an optional backing plate <b>550</b>. Club head mass may be distributed about the perimeter of the club body <b>510</b> based on a particular mass distribution for the club head <b>500</b> selected by a club head designer, as discussed previously in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.

0093As shown in <figref idref="DRAWINGS">FIG. 5A</figref>, the striking plate <b>530</b>, the optional backing plate <b>550</b>, and the head body <b>510</b> are preferably formed separately. In such a design, the completed club head is made by securing the striking plate <b>530</b> and the optional backing plate <b>550</b> to the mounting area <b>521</b> by bonding with an adhesive, welding, or other process. The mounting area <b>521</b> defines a recess, or pocket, formed in the forward surface of the club head body <b>510</b>. In the embodiment shown, the perimeter of the recess defined by the mounting area <b>521</b> is slightly larger than the perimeter of the striking plate <b>530</b> and the optional backing plate <b>550</b>, thereby providing for the ability to position the striking plate <b>530</b> and backing plate <b>550</b> into the recess. A gap or seam <b>524</b> is thereby defined between the walls of the recess of the mounting area <b>521</b> and the perimeter of the striking plate <b>530</b>. In some embodiments, the seam <b>524</b> has a width that is preferably less than about 0.5 mm, such as less than about 0.25 mm, such as less than about 0.1 mm. In alternative embodiments, the club head body <b>510</b> does not include a recessed mounting area <b>521</b>. Instead, the striking plate <b>530</b> and optional backing plate <b>550</b> are secured directly to the forward-facing surface of the club head body <b>510</b>, and no gap or seam <b>524</b> is formed.

0094A front surface <b>522</b> of the club is defined by both a striking surface <b>532</b> of the striking plate <b>530</b> and portions <b>526</b> of the club body <b>510</b>. The front surface <b>522</b> can be polished, blasted using an abrasive media, or ground to remove any front surface edges situated at the striking plate/club body seam <b>524</b>. In some examples, the portions <b>526</b> are polished and the front surface <b>532</b> of the striking plate <b>530</b> is finely ground. The striking surface <b>532</b> is a substantially planar grooved surface configured to strike a golf ball, although for some players, other portions of the front surface <b>522</b> also contact the golf ball.

0095As noted above, grinding, blasting, polishing, and/or coating (e.g., PVD coating) operations can be used to remove any excess material or irregularities introduced in the bonding, welding, or other process, or to provide a selected club head appearance such as, for example, a specularly reflective polished appearance, a fine ground appearance, a black or darkened appearance, or other appearance. The striking plate <b>530</b> preferably includes a set of grooves, such as exemplary grooves <b>535</b>, <b>536</b> formed in the striking surface <b>532</b>. The striking plate <b>530</b> may also include an additional surface texture, such as secondary surface markings <b>537</b> (see, e.g., <figref idref="DRAWINGS">FIGS. 5B and 5D</figref>). The grooves <b>535</b>, <b>536</b> and secondary surface markings <b>537</b> are similar to those described previously in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>.

0096In some embodiments, the head body <b>510</b> is formed by casting, forging, stamping, or other known manufacturing process, using the processes and materials described above in reference to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. Similarly, in the embodiment shown, the striking plate <b>530</b> is formed using an electroforming process, which is also described above in relation to the embodiments illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. The striking plate <b>530</b> includes pluralities of projections <b>538</b> and recesses <b>539</b> on its rear surface, and includes thickness ranges for the thicknesses t<b>1</b>, t<b>2</b>, t<b>3</b>, and t<b>4</b> as described above in relation to the striking plate <b>130</b> illustrated in <figref idref="DRAWINGS">FIGS. 1A-1F</figref>. The cross-sections of the rear surface projections <b>538</b> and recesses <b>539</b> shown in <figref idref="DRAWINGS">FIG. 5B</figref> are merely one example, as square, trapezoidal, semicircular, triangular, or other shapes for the projections and/or recesses can be used. Moreover, different cross-sectional shapes and dimensions can be used in different portions of the striking plate <b>530</b>.

0097Turning to <figref idref="DRAWINGS">FIGS. 5C-5D</figref>, the optional backing plate <b>550</b> includes a forward surface <b>552</b> and a rear surface <b>553</b>. In the embodiment shown, the backing plate <b>550</b> is substantially flat on both its rear surface <b>553</b> and on its forward surface <b>552</b> and has a nominal thickness t<b>16</b>. In some embodiments, the thickness t<b>16</b> of the backing plate <b>550</b> may be from about 0.1 mm to about 3.0 mm, such as from about 0.20 mm to about 2.0 mm, such as from about 0.25 mm to about 1.0 mm. In the embodiment shown, the backing plate <b>550</b> includes a plurality of square through-holes <b>557</b> that extend completely through the backing plate <b>550</b> from the forward surface <b>552</b> to the rear surface <b>553</b> and that are separated by substantially flat reference areas <b>556</b>. In some embodiments, the width (t<b>14</b>) of the through-holes <b>557</b> is substantially equal to the width of the projections <b>538</b> formed on the rear surface of the striking plate <b>530</b>, and the width (t<b>15</b>) of the reference areas <b>556</b> is substantially equal to the width of the recesses <b>539</b> formed on the rear surface of the striking plate <b>530</b>. The locations, sizes, and cross-sectional shapes of the through-holes <b>557</b> and reference areas <b>556</b> shown in <figref idref="DRAWINGS">FIGS. 5C-5D</figref> are merely one example, as round, triangular, trapezoidal, rectangular, or other geometric or non-geometric shapes for the through-holes <b>557</b> and reference areas <b>556</b> can be used. Moreover, different cross-sectional shapes and dimensions can be used in different portions of the backing plate <b>550</b>.

0098The backing plate thicknesses t<b>16</b> will be dependent upon the material of the backing plate <b>550</b> and the desired performance objectives for including the backing plate, among other factors. The striking plate <b>530</b> and backing plate <b>550</b> can be attached to the club head body <b>510</b> by adhesive bonding, soldering, brazing, welding, mechanical fastening, riveting, screwing, etc. In the embodiment shown in <figref idref="DRAWINGS">FIG. 5D</figref>, the backing plate <b>550</b> is attached to the club head body <b>510</b> by a first adhesive layer <b>554</b>, and the striking plate <b>530</b> is attached to the backing plate <b>550</b> by a second adhesive layer <b>534</b>. The adhesive materials used in the first adhesive layer <b>554</b> and second adhesive layer <b>534</b> can be the same as those used in the adhesive layer <b>134</b> described above in relation to the embodiments illustrated in <figref idref="DRAWINGS">FIGS. 1A-F</figref>.

0099As shown, for example, in <figref idref="DRAWINGS">FIG. 5D</figref>, in some embodiments, the through-holes <b>557</b> on the backing plate <b>550</b> are generally aligned, center-to-center, with respective ones of the recesses <b>539</b> formed on the rear surface of the striking plate <b>530</b>. In other embodiments, the through-holes <b>557</b> may be generally aligned, center-to-center, with respective ones of the projections <b>538</b> formed on the rear surface of the striking plate <b>530</b>. In still other embodiments, the through-holes <b>557</b> of the backing plate <b>550</b> may have an aligned that is offset by a defined distance from the centers of either the recesses <b>539</b> or the projections <b>538</b> of the striking plate <b>530</b>. In still other embodiments, there may be no correlation between the locations of the through-holes <b>557</b> on the backing plate <b>550</b> and the locations of the projections <b>538</b> and recesses <b>539</b> on the striking plate <b>530</b>.

0100In the embodiments shown and described above in relation to <figref idref="DRAWINGS">FIGS. 3A-D</figref>, the striking plate projections <b>338</b> are aligned with the backing plate recesses <b>357</b>, and the striking plate recesses <b>339</b> are aligned with the backing plate projections <b>356</b>. This alignment results in a substantially uniform thickness for the adhesive layer <b>334</b> located between the striking plate <b>330</b> and the backing plate <b>350</b>. On the other hand, in the embodiments shown and discussed above in relation to <figref idref="DRAWINGS">FIGS. 4A-4D</figref>, the striking plate projections <b>438</b> are aligned with the backing plate projections <b>456</b>, and the striking plate recesses <b>439</b> are aligned with the backing plate recesses <b>457</b>. This alignment results in an adhesive layer <b>434</b> located between the striking plate <b>430</b> and the backing plate <b>450</b> that has a varying thickness. In still another example, in the embodiments shown and discussed above in relation to <figref idref="DRAWINGS">FIGS. 5A-D</figref>, the striking plate projections <b>538</b> are aligned with the backing plate reference areas <b>556</b>, and the striking plate recesses <b>539</b> are aligned with the backing plate through-holes <b>557</b>. This alignment results in an second adhesive layer <b>534</b> located between the striking plate <b>530</b> and the backing plate <b>550</b> that has a varying thickness and that extends through the through-holes <b>557</b> to meet the first adhesive layer <b>554</b>. In still other embodiments, the respective alignments of the striking plate and backing plate, as well as the projections and recesses (if any) contained on the striking plate and the projections, recesses, and through-holes (if any) contained on the backing plate, may be offset from the alignments shown in <figref idref="DRAWINGS">FIGS. 3A-3D, 4A-4D, and 5A</figref>-D. In still other embodiments, first portions of the striking plate and backing plate include projections, recesses, and/or through-holes having a first alignment, while second portions of the striking plate and backing plate include projections, recesses, and/or through-holes having a second alignment. In still other embodiments, first portions of the striking plate and backing plate include projections, recesses, and/or through-holes while second portions of the striking plate and backing plate do not include projections, recesses, or through-holes. Various other combinations are also contemplated.

0101The various shapes, sizes, and orientations of the described embodiments of the striking plates, backing plates, and adhesive layers are selected to achieve desired performance objectives, such as (without limitation) to change (increase or decrease) the coefficient of restitution (COR) and/or characteristic time (CT) at one or more locations of the striking plate, to improve the durability of the striking plate and/or the club head, to improve the sound or feel of the club head upon impact with a golf ball, or to improve other performance objectives. The materials and layer thicknesses of these components may also be varied to achieve these objectives.

0102One advantage of the embodiments described above is that the face insert is significantly more durable than a comparable face insert manufactured according to conventional casting or machining processes. The electroforming method of manufacture provides face inserts having increased hardness and durability that are able to withstand a significantly higher number of high speed strikes with a golf ball and that have significantly increased resistance to scratching and scuffing when golf balls are struck in the presence of sand (bunker shots). Another advantage of the embodiments described above is that the face insert is formed in a more precise manner, leading to a significantly higher manufacturing yield in comparison to casting or machining processes used to manufacture conventional face inserts.

0103It is apparent that the examples described above are representative of the disclosed technology, and that other examples can be provided. Thus, these examples are not to be taken as limiting, and we claim all that is encompassed by the appended claims and the equivalents thereof.

0104In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.